The present application relates generally to an improved data processing apparatus and method and more specifically to mechanisms for saving power by logical partition defragmentation within a data processing system.
A logical partition, commonly called an LPAR, is a subset of hardware resources, virtualized as a separate computer. In effect, a physical machine can be partitioned into multiple logical partitions, each hosting a separate operating system. A logically partitioned platform may include partitioned hardware, operating systems, and partition management firmware. The operating systems may be multiple copies of a single operating system or multiple heterogeneous operating systems simultaneously run on the logically partitioned platform. These operating systems may be designed to interface with a virtualization mechanism, such as partition management firmware, e.g., a hypervisor.
Hypervisor software is an example of software that may be used to implement partition management firmware and is available from International Business Machines Corporation. Firmware is “software” stored in a memory chip that holds its content without electrical power, such as, for example, a read-only memory (ROM), a programmable ROM (PROM), an erasable programmable ROM (EPROM), and an electrically erasable programmable ROM (EEPROM). The logical partitions may also include partition firmware.
When logical partitions are instantiated, a copy of the boot strap code is loaded into the logical partitions by the platform firmware. Thereafter, control is transferred to the boot strap code with the boot strap code then loading the open firmware and RTAS. The processors associated or assigned to the logical partitions are then dispatched to the logical partition's memory to execute the logical partition firmware.
The partitioned hardware may include a plurality of processors, a plurality of system memory units, a plurality of input/output (I/O) adapters, and a storage unit. Each of the processors, the memory units, and the I/O adapters may be assigned to one of the multiple logical partitions within the logically partitioned platform, each of which corresponds to one of a plurality of operating systems.
The platform firmware performs a number of functions and services for the logical partitions to create and enforce the partitioning of the logical partitioned platform. The platform firmware is a firmware implemented virtual machine identical to the underlying hardware. Thus, the platform firmware allows the simultaneous execution of independent operating system images by virtualizing all the hardware resources of the logical partitioned platform.
A service processor may provide various services, such as processing of platform errors in the logical partitions. The service processor may also act as a service agent to report errors back to a vendor. Operations of the different logical partitions may be controlled through a hardware management system. The hardware management system is a separate data processing system from which a system administrator may perform various functions including reallocation of resources to different logical partitions.
The partition management firmware may have the capability to migrate logical partitions (Live Partition Mobility) between physical servers. Thus, the firmware may have the capability to consolidate partitions to a single server depending on the workload. Live Partition Mobility is very good when entire servers can be powered down by consolidating logical partitions from different servers to a single server.